Ink-jet recording is carried out in such a manner that fine droplets of ink are allowed to fly employing various operation principles and are thus adhered onto a recording sheet such as a sheet of paper to record images and characters. Ink-jet recording exhibits advantages such as relatively high speed, low noise, ease of multicolored image production. And thus, ink-jet recording has been rapidly applied to a variety of fields. Ink-jet recording is employed for producing a photographic like print, which requires high image quality printing. In this case, it is required for a recording sheet to have high ink absorption property, to be free from a foreign matter and cracking on a sheet, and to achieve high productivity.
In order to overcome these problems, conventionally, numerous techniques have been proposed.
For example, Japanese Patent Publication Open to Public Inspection No. 52-53012 describes an ink-jet recording medium (hereinafter referred to also as a recording medium) in which a minimally sized paper support is dampened with paint employed for surface treatment; Japanese Patent Publication Open to Public Inspection No. 55-5830 describes a recording medium comprising a support in which an ink absorbing coating layer is provided on the surface of the support; Japanese Patent Publication Open to Public Inspection No. 56-157 describes a recording medium comprising a covering layer containing non-colloidal silica powder as a pigment; Japanese Patent Publication Open to Public Inspection No. 57-107873 describes a recording medium comprising an inorganic pigment and an organic pigment in combination; Japanese Patent Publication Open to Public Inspection No. 58-110287 describes a recording medium which exhibits a void size distribution value with two peaks; Japanese Patent Publication Open to Public Inspection No. 62-111782 describes a recording medium composed of an upper porous layer and a lower porous layer; Japanese Patent Publication Open to Public Inspection Nos. 59-68292, 59-123696, 60-18383 describe a recording medium featuring amorphous cracking; Japanese Patent Publication Open to Public Inspection Nos. 61-135786, 61-148092, 62-149475 describe a recording medium having a fine powder layer; Japanese Patent Publication Open to Public Inspection Nos. 63-252779, 1-108083, 2-136279, 3-65376, 3-27976 describe a recording medium comprising pigments and fine silica particles having specified physical parameters; Japanese Patent Publication Open to Public Inspection Nos. 57-14091, 60-219083, 60-210984, 61-20797, 61-188183, 5-278324, 6-92011, 6-183134, 7-137431, 7-276789 describe a recording medium containing fine silica particles such as colloidal silica; Japanese Patent Publication Open to Public Inspection Nos. 2-276671, 3-67684, 3-215082, 3-251488, 4-67986, 4-263983, 5-16517 describe a recording medium containing fine hydrated alumina particles. However, these have not been fully adequate to overcome said problems.
Furthermore, Japanese Patent Publication Open to Public Inspection No. 2001-149856 describes a preparation method of a coating composition in which is added a water-soluble polymer to a dispersion of silica after standing still, or without agitation for more than 5 hours. However, this production method results in low productivity, and the printing quality and the quality of the coated layer are not fully satisfactory.